One aspect of application development is the design and fine-tuning of the user interface of the application. Conventionally, modifications of the user interface of an application during development are made to the source code of the application in an application development environment, and the code must then be recompiled for a given target client device, reinstalled on the client device, and then executed to determine whether the modifications are acceptable. If not, the developer needs to return to an application development environment, modify the source code again, recompile, reinstall the application on the client, and execute the application. Similar difficulties are encountered when modifying other aspects of an application, such as functional behavior, algorithms, or other operations. Each time a change is made, evaluation of the change requires a recompile, install and execute cycle. This process is extremely time consuming and inefficient for the application developer.